Lead acid batteries have evolved, over time, as the demands for a source of mobile electric power have grown. This technology is getting ready to evolve once again with the rising popularity of the hybrid electric vehicle (HEV) or ‘micro HEV.’ The demands on the battery for the HEV are different from those of the conventional gasoline powered vehicle. For example, the HEV's battery will operate in a partial state of charge (PSoC), approximately 50 to 80% charge. As such, the battery will undergo shallow charge/recharge cycles, and will not undergo overcharge where dissociation of water evolves hydrogen and oxygen that mixes stratified acid within the cell. Additionally, retention of active material is also an issue that must be addressed.
Accordingly, there is a need for new separator technology to meet and overcome the new challenges arising with the advent of the HEVs.